Yenra : Air Travel : X2 Coaxial Helicopters : Two rotors on the same axis and a pusher prop to supply auxiliary propulsion enables speeds of 250 knots an hour


Sikorsky Aircraft today announced plans to build and test a demonstrator for a new class of coaxial X2 Technology helicopters that maintain or improve on all the vertical flight capabilities of rotorcraft and whose high speed configuration will cruise at 250 knots.

Sikorsky plans to build and fly its X2 Technology demonstrator helicopter at its Schweizer Aircraft subsidiary by the end of 2006. Preliminary design work for the demonstrator is finished and parts fabrication for the aircraft has commenced.

X2 Technology refers to a suite of technologies Sikorsky will apply to achieve new levels of speed and performance in coaxial helicopters. Coaxial helicopters feature two counter-rotating rotors on the same vertical axis.

The announcement came at the American Helicopter Society International's annual technical forum in Grapevine, Texas, where Sikorsky unveiled new scale models of X2 Technology helicopter concepts in various weight classes and configurations.

"We initiated X2 Technology convinced that the most productive and flexible helicopter is a helicopter which is capable of a significant increase in speed," said Sikorsky President Stephen Finger. "Customers are demanding greater speed but without sacrificing any of the unique capabilities that make helicopters the ideal platform for countless civil and military missions."

X2 Technology aircraft will hover, land vertically, maneuver at low speeds, and transition seamlessly from hover to forward flight like a helicopter. In a high speed configuration, one or more pusher props are part of an integrated auxiliary propulsion system to enable high speed with no need to physically reconfigure the aircraft in flight.

The top cruise speed of helicopters in service today, roughly 150 to 170 knots, are only incrementally better than what they were decades ago due to the fundamental limits of conventional rotor systems.

Previous attempts to develop faster helicopters have resulted in degraded hover performance. Likewise, attempts at fixed wing or hybrid vertical lift aircraft have resulted in aircraft with less hover capability than helicopters.

Sikorsky selected the term X2 Technology in order to describe a class of helicopters with a coaxial design, describe the multiplying effect of applying a suite of modern technologies to coaxial helicopters. These technologies include new rotor blade designs, advanced flight control laws, transmissions with greater horsepower to weight performance and the ability to seamlessly transfer power from the main rotor to the aft propulser, and active vibration control.

Sikorsky will incorporate decades of company research and development into X2 Technology helicopters.The XH-59A Advancing Blade Concept Demonstrator showed high speed was possible with a coaxial helicopter and auxiliary propulsion. The Cypher UAV expanded company knowledge of the unique aspects of flight control laws in a fly by wire aircraft that employed coaxial rotors The RAH-66 Comanche developed expertise in composite rotors and advanced transmission design.

Sikorsky (now part of Lockheed Martin) designs, manufactures, and services helicopters.